Posted on 03/17/2020 4:34:32 PM PDT by gas_dr
I have spent the last several days like most Americans somewhat baffled, perplexed and even a little nervous at the rapidly unfolding events as to CoVID-19. The community seems to have been divided into two groups, those who are advocating that there is nothing more than the common flu here and that there is vast overreaction, and those that advocate that this is a serious illness that for the safety of all requires drastic measures in order to prevent mass death and tragedy. If one looks closely, it is possible to find everything from death rates calculated at 0.1% - 14% and beyond.
Fair warning, I tend to fall in the previous camp and think that this is likely an overblown situation that appears to be gathering inertia, and I have gotten into several heated and admittedly emotional arguments about this current situation. For full disclosure, I am a critical care physician practicing in the United States, and the fear of the unknown probably drives to a small degree my emotion. So this evening, I have decided to put emotion aside, and truly conduct a retrospective analysis of the data that is present in a multivariant system and see where the data lead us.
I have discovered something interesting, and will simply present the data without commentary. I have analyzed from the worldometer website six countries: China, Italy, United States, South Korea, Spain, and France. I have been curious as to the timelines and increase in daily cases in countries that appear to have rampant disease, and countries that have flattened the curve.
Methodology: Utilizing a base case rate of 100 infections, I standardized the time to 6340 infections, which happens to be the current report of United States infections updated at 1800 EDT. Datasouce: Worldometers.info
CHINA: Time to equivalent cases of United States infections: +7 days. (571 cases -> 7,711 cases). Time to Peak of newly reported cases (2nd inflection point) +15 days from current US case load. After inflection point, total new cases fell dramatically
South Korea: Time to equivalent cases of United States Infections: +15 days (100 cases - 6593 cases). Time to peak of newly reported cases (2nd inflection point) +4 days. After inflection point, total new cases fell dramatically.
Italy: Time to equivalent cases United States Infections: +15 days. (75 - 6,387). Time to peak of newly reported cases +7 days. This is where the data may become predictive. Between March 15, 16, and 17 there was a relatively flattening of new cases and decline in the last 24 hours reported period. What will be a test of this model is what happens to the cases in this 24 hour period. According to the other models, this should be the peak.
United States: Time from 100 cases - 6340 cases +15 days. If this model is predictive, we can ascertain in the next 4 - 7 days based on number of cases and shape of curve if we appear to follow South Korea numbers, or Italian and China Numbers. The current acting head of HHS repeatedly states out numbers track South Korea.
Spain: Time from 75 cases - 6391 cases +13 days. Today is day +2 from the relatively time constant 100 -> 6500 cases period.
France: Time from 100 cases - 6633 cases +16 days. Today is day +1 from relative time constant too >6000 cases.
Analysis: At this time, in the six major countries actively reporting all cases and under greatest scrutiny, there appears to be a constant of +14 days to grow from 100 - 6500 cases. The percentage variation in this is extremely small. From the time this 15 day time constant occurs, there is divergent data to the second inflection point in countries who are reporting a decrease in overall numbers of new cases (curve flattening). That time constant is from 4 - 7 days (South Korea (4) - China (7) - Italy (7)) If this is predictive model, what we should see it a flattening of the Italian curve starting today -- that would track with China. In the United States we are between (4) and (7) days from flattening if the data hold. The divergence of cases added between day 4 and day 7 are as few as 1500 new cases as in South Korea, and as many as 20,300 new cases in Italy, which fits an exponential growth from day 4 - 7.
If the Italian numbers are flat tomorrow and the next day, the model appears will become increasingly predictive. Questions that remain to be answered: Are aggressive measures able to reduce the time to second inflection as in the case of South Korea? If so, then we can predict in America that maximal saturation will be March 21. If it trends toward China and Italy, then it will be March 24.
I will update this as data become available. I look forward to reasoned discussion regardless of personal opinion as to the scope of this pandemic.
Reports from Italy are that up to 40% of population is violating the quarantine.
After Lombardy shut down, there was a mass exodus of people taking trains from Milan area to the southern regions (before the entire country was put on lockdown).
Now it’s just starting to infect the migrant hospitality centers. Ouch.
Korea ramped up at the exact time constant 15 days. It is fascinating as they were ahead of the testing curve. What is interest about South Korea is that they have 7000 plus (+) in the roughly 160,000 tests. Given this, and assuming testing was based on either self reported symptoms or health care referrals, the actually penetrance is 4%. Fauci commented on penetrance today that we dont know. My suspicion is as follows:
1. For every 1 infection there are 9 that are asymptomatic or did not make it to to medical system contact
2. There are likely a lot o serologically (+) cases that drive the actual critical and death rate down
Given the behavior of the US, I would presume that we are going to track the South Korean trajectory, That would make second inflection point On March 21, or 22 — a good day for the Spring Solstice.
Yeah, I have been more of a jackass than usual the last couple of days — but your kindness has been appreciated.
The number of US cases that are Serious or Critical (worldometers.info) also seems anomalously low (under 20?).
The low number of recoveries is because the cases are still classified as active, that is what makes the death cs recovery interesting and the parallel at 50% at around day 11. We should forecast the rapid increase in recoveries and diminishment of death over the next several days.
Otherwise, this is very different here than anywhere else, and then all bets are off.
So the US ramped up (in our own way and including travel restrictions) BEFORE 15 days, as opposed to S.K.
“These are the times that try men’s souls.”
Germany, too. Only 2 of 9,274 active cases are listed as Serious/Critical.
Better drugs being given to patients in the early stages?
Bump Thanks Doc.
Thank you for your kindness. Stay safe.
You know when I was looking at the data that period in the China data did stand out — it was pretty fascinating, I cannot wait to hear your analysis. Clearly your expertise there supersedes mine. Look forward to your erudite analysis.
Its a badge of honor to have received your bring out your dead tag. Thanks! :)
I believe DoodleBob is bringing forth in oncoming days his logistic data curve. I look forward to his analysis.
Thanks for the post, gas_dr. I feel like I may know you from somewhere in the past.
Stay safe, stay vigilant, and thanks again for the info.
Interesting. Bump to watch
Does weather and climate have anything to do with the numbers?
This is just the data from the aggregate world data. I have not looked at meteorological events.
Seems to me that the test rate might be impacting the numbers we are all considering and in that case might be misleading if trying to compare totals without calculating the difference in the test rates. Another factor in all of this is Mother Nature and when she arrives in warm enough fashion to expedite the end of this virus. Since we are getting hit after the others and our weather is closer to spring, we might have less to worry about. Your efforts are much appreciated and certainly give us a slightly different perspective of the time frame.
The serious flaw in these calculations and graphs is they fail to normalize for population. Spain, France, Italy, Iran and South Korea have populations in the 50 - 60 million range. The US has over 300 million. Choosing a flex point of 100 cases for the other countries equates to roughly 500 cases in the US. Also significant in evaluating the US is the fact that between 20 and 30 cases were imported from China or cruise ships. That number would not create a significant deviation at 500 - 600 case flex point but is highly significant at 100 cases.
The methodology applied is commendable but fails to account for all significant variable with respect to the US.
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